Engine construction



W. S HARLEY. iNGINE CUNSTHUCHON. MPLELATIGN mm SEPI. 19. 19:7

3 SHEETSSHEET 1.

Patented Nov. 23, 1920.

{r b H c W. S, HARtEY ENGINE CONSTRUCTION.

MPLICAHON FILED sum a9. 1911 1 ,360, 1 10, Patented Nov. 23, 1920 3SHEETS-SHEET 2.

RE/140M (m? w. s. HARLEY ENGINE CUNSMUG'HON. AiPHCANON FILED SEPT 19.191 I. 1,360, 1 1() atented Nov. 23, 1920.

3 SHEETS-SHEET 3.

companion applications Serial Nos. 192,116,

UNITED STATES PATENT OFFlCE.

WILLIAM S. HARLEY, OF MILWAUKEE, WISCONSIN. ASSIGNOB TO HARLEY-DAVIDSONMOTOR 60.. 0F MILWAUKEE, WISCONSIN.

ENGINE CONSTRUCTION.

Specification 01' Letters Patent.

Patented Nov. 23, 1920.

Application filed hepcember 19, 1917. Serial No. 192,117.

To all whom it may concern lie it known that 1. human S. HARLEY, acitizen of the l nited States. and resident of Milwaukee. in the countyof Milwaukee and State of Wisconsin. have invented certain new anduseful Improvements in Enginc (onstructiom and I do hcrebyvdeclare thatthe following is a full. clear, and exact description thereof.

My present invention relates to improvements in internal combustionengine structure, particularly that type of engine adapted for use onmotorcycles and similar light vehicles.

The principalohjcct of the invention is to produce a simply constructedand a light internal combustion engine for motorcycles, which will beextremely compact. lVith this object in view a radical departure in theappearance ofsuch engines has been made, the opposed cylinder type beingmodified and "eqnipped with improvements to allow its eingused onmotorcycle frames.

In attaining a compact and li ht engine the usual crank case has beenmodified to allow the selective gear transmission mechanism to bemounted therein.

A further object of the invention is to provide an improved arrangementfor actu ating the valves of the opposed cylinders of the motor.

A still further object is to rovide an improved closure cap for thefilling opening of the crank case.

W'ith these and other objects in view. the invention resides in thenovel features of construction. combination and arrangement of parts,which will be hereinafter more particularly claimed and' shown in thedrawing W erein: t

Figure 1 represents a substa n 1 lly vertical transverse sectional viewtlirough a motorcycle power plant constructed in accordance with myinvention.

Fig. 2 is a vertical sectiontaken substantially on the line 2-2 ofFig. 1. r

' Fig. 3 is a similar view on the plane of the line 33 of Fig. 1, and

Fig. 4 is a detail elevational view showing the means for holding theshiftahle gear of the selctive speed transmission mechanism in any oneof its four positions.

Inasmuch as several of the featuresillustrated in'the drawings of thepresent invention form the subject matter of co-pending mounted.

site side wall substantially intermediate the ends, these openingsreceiving' the inner ends of horizontally positioned opposed engine 0linders 3 and 4 in which pistons (not siown) are designed toreciprocate, and means for translating the reciprocativc mo tion of saidpistons to the rear wheel of a motorcycle. 11 the lower end of the crankcase 1 15 disposed a crank shaft 5 to which the pistons are connected,the straight portions of said crank shaft being journally mounted in theside Walls 6 and 7 of said case 1. Both ends of said crankshaft extendoutwardly of the crank case, one being provided with a fly wheel 8 andthe other with a spur gear 9.

The gear 9 is disposed in engagement with the outer side of the Wall 6,the latter, together with a crank case cover 10, forming a gear case tohouse the train of 'gears of which the gear 9 forms a unit,and theclutch 11. One of the units of said train of gears operates an oiler 12,which is constructed in accordance with Letters Patent No. 1,254,799granted to me on January 29.

The clutch 11 forms a part of a selectiv speed transmission mechanismand is mounted upon one end of a drive-shaft 13, which is journallymounted in bearings in the walls 6 and 7 of the crank case adjacent thetop thereof, said shaft being extended parallel to the crank shaft andtherefore transversely of the crank case. A sprocket wheel 14 connectedwith the end of the drive shaft 13 on the opposite side of the crankcase from the clutch 11 is adapted to have a sprocket chain trainedthereover and around the sprocket on the rear wheel of a motorcycle uponvvhich the. power plate is As inall transmission mechanism, the clutch11 is designed to disengage a drive shaft 13 fromthe c'rank shaft 5.toalloy a shiftable gear 15 to be meshed with any one of three othengearsso as to change the speed ratio between the rank shaft and the.motorcycle drive wheel, or moved into a-

